Differences in Function Exporting

To export your function from C# to UnigineScript, you should use Interpreter.Function() with different postfixes instead of MakeExternFunction(). The postfix of Function shows the number of arguments (up to 8 arguments) and the type of return value:

Read about the C++ API Unigine::Renderer class which has the same methods and behavior as in the C# API.

Using References

You can add your .dll libraries to the C# project to use specific structures, classes and methods. If you use Visual Studio you can add NuGet packages to your solution by clicking Project -> Manage NuGet Packages...

View Documentation by Using Visual Studio

You can read the documentation of some of C# API methods by using the Object Browser in Visual Studio.